204 Print Reading for HVACR
Copyright Goodheart-Willcox Co., Inc.
This diagram provides a combination of easily recognizable components
and some features commonly found on schematic diagrams. The pictorial
diagram in Figure 9-5 includes a solid-state control board. This type of
pictorial diagram is useful when a service technician needs to know the
exact location of a particular terminal on the board or where one of the
system components, such as the inducer motor, is connected.
Another variation of the pictorial diagram is shown in Figure 9-6.
This is a diagram of a solid-state HVACR system control board that
includes multiple relays, chips, and modules. Each item in the diagram is
coded and can be easily located because the positions of the components
on the diagram are the same as on the actual board.
9.2.2 Schematic Wiring Diagrams
A schematic diagram is a detailed illustration of the wiring in a piece
of equipment or device. Each wire in the circuit appears on the dia-
gram, along with its color and associated electrical connections. The
circuit wiring of the system is represented by lines, and its components
and associated terminals are identifi ed by symbols. See Figure 9-7.
Other information may be included in the diagram, such as the wire
gage, circuit voltage, and factory- and fi eld-installed wiring.
Junction box
Hot
Ground
Neutral
G
W
BK
Interlock switch
BK
BK
BK
BK
BK
BK
BK
BK
W W
W
W
W
W G Y C R
W
BL
R
BR
BR
W
W W
BL
Gas valve
Y
R R R
R
R
P
P
Y
BL
Limit Roll out Roll out
Pressure switch
R
G
G
R
Transformer
Cool M1 M2 Heat
R
G
O
FS HSI
IND
L1 XFRM PRI
Neutrals
W
O
Hot surface igniter
Flame sensor
Low speed
High speed
Medium
Neutral
Capacitor
Blower Motor
Inducer Motor
Line voltage
Low voltage
BR -Brown
BK -Black
BL -Blue
G -Green
O -Orange Y -Yellow P -Purple
Legend
Jason Obrzut
Figure 9-5. The pictorial wiring diagram of a system that utilizes a solid-state control board.
Copyright Goodheart-Willcox Co., Inc.
This diagram provides a combination of easily recognizable components
and some features commonly found on schematic diagrams. The pictorial
diagram in Figure 9-5 includes a solid-state control board. This type of
pictorial diagram is useful when a service technician needs to know the
exact location of a particular terminal on the board or where one of the
system components, such as the inducer motor, is connected.
Another variation of the pictorial diagram is shown in Figure 9-6.
This is a diagram of a solid-state HVACR system control board that
includes multiple relays, chips, and modules. Each item in the diagram is
coded and can be easily located because the positions of the components
on the diagram are the same as on the actual board.
9.2.2 Schematic Wiring Diagrams
A schematic diagram is a detailed illustration of the wiring in a piece
of equipment or device. Each wire in the circuit appears on the dia-
gram, along with its color and associated electrical connections. The
circuit wiring of the system is represented by lines, and its components
and associated terminals are identifi ed by symbols. See Figure 9-7.
Other information may be included in the diagram, such as the wire
gage, circuit voltage, and factory- and fi eld-installed wiring.
Junction box
Hot
Ground
Neutral
G
W
BK
Interlock switch
BK
BK
BK
BK
BK
BK
BK
BK
W W
W
W
W
W G Y C R
W
BL
R
BR
BR
W
W W
BL
Gas valve
Y
R R R
R
R
P
P
Y
BL
Limit Roll out Roll out
Pressure switch
R
G
G
R
Transformer
Cool M1 M2 Heat
R
G
O
FS HSI
IND
L1 XFRM PRI
Neutrals
W
O
Hot surface igniter
Flame sensor
Low speed
High speed
Medium
Neutral
Capacitor
Blower Motor
Inducer Motor
Line voltage
Low voltage
BR -Brown
BK -Black
BL -Blue
G -Green
O -Orange Y -Yellow P -Purple
Legend
Jason Obrzut
Figure 9-5. The pictorial wiring diagram of a system that utilizes a solid-state control board.